Large eddy simulation of a 3-D spatially developing turbulent round jet

Zhang, Huiqiang; Rong, Yi; Wang, Bing; Wang, Xiaohao

doi:10.1007/s11431-011-4577-8

Cited by 8 publications

(2 citation statements)

References 21 publications

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“…Zhong et al [33] observed curved martensite/austenite interfaces in an 0.2C-1.5Si-1.67Mn (wt pct) steel after full austenitization, quenching to 523 K (250°C) and partitioning at 753 K (480°C) for 80 seconds, which were not observed after partitioning for 6 seconds. However, the exact relation of these curvatures with the original grain shape was not reported.…”

Section: Microstructural Changes During Quenching and Partitionimentioning

confidence: 99%

Overview of Mechanisms Involved During the Quenching and Partitioning Process in Steels

Santofimia

Zhao

Sietsma

2011

Metall Mater Trans A

113

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The application of the quenching and partitioning (Q&P) process in steels involves a microstructural evolution that is more complex than just the formation of martensite followed by carbon partitioning from martensite to austenite. Examples of this complexity are the formation of epitaxial ferrite during the first quenching step and the formation of bainite, carbides, and carbon gradients as well as migration of martensite/austenite interfaces during the partitioning step. In this work, recent investigations on the mechanisms controlling microstructural changes during the application of the Q&P process are evaluated, leading to phase-formation based concepts for the design of Q&P steels. NEW strategies for the creation of advanced high strength steels with improved mechanical properties of strength, toughness, and ductility are based on the development of microstructures consisting of ultrafine phases formed in nonequilibrium conditions such as martensite and bainite in combination with retained austenite. [1] The refined and highly dislocated martensite and bainite contribute to a simultaneous increase of strength and toughness. Retained austenite contributes to the improvement of the strength/ductility combination via the transformation induced plasticity (TRIP) effect and to the improvement of the toughness if the retained-austenite grains have a filmlike morphology. One of the most innovative procedures to create microstructures consisting of martensite and retained austenite is the so-called quenching and partitioning (Q&P) process. [2] This process starts with a total or partial austenitization, followed by a quench of the microstructure to a temperature (quenching temperature) below the martensite start (M s ) temperature but above the martensite finish (M f ) temperature to form a controlled fraction of martensite. This microstructure is then subjected to a treatment at the same or higher temperature (partitioning temperature) in order to accomplish the carbon diffusion from the carbon-supersaturated martensite to the neighboring austenite. Finally, the material is quenched to room temperature and the austenite that has been sufficiently carbon enriched remains metastable at room temperature, whereas the rest transforms into martensite.Investigations on the Q&P process were mainly focused on the application of this heat treatment to steels with chemistries very close to commercial TRIP steels, [3][4][5][6][7][8] designed to promote bainite formation, whereas studies on steels specially designed to be subjected to the Q&P process are fewer. [9][10][11] Depending on the steel composition and the particular heat treatments, formation of bainite, ferrite, and carbides during the Q&P process can overlap with carbon partitioning from martensite to austenite, reducing the effectiveness of this heat treatment leading to the desired microstructures. An adequate theoretical knowledge of the mechanisms occurring during the Q&P process would lead to a well control of these overlapping phenomena. In the present work, ...

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Section: Microstructural Changes During Quenching and Partitionimentioning

confidence: 99%

Overview of Mechanisms Involved During the Quenching and Partitioning Process in Steels

Santofimia

Zhao

Sietsma

2011

Metall Mater Trans A

113

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“…In the partitioning process, the possible interface migration of martensiteaustenite, which was induced by carbon diffusing from martensite to austenite, is observed by the experimental in-situ detection, although the direction of the interface movement has not been established. [67] Recently, a theoretical possibility explaining the interface motion is simulated by a model based on thermodynamics and diffusion. [68,69] A crooked interface between the martensite and retained austenite during Q&P at 453 K (180°C) for 1800 seconds may indicate that carbon partitioning results in the interface movement from martensite to austenite, namely the growth of the existing martensite, as is shown by the arrow in Figure 11.…”

Section: B Microstructure Of One-step Quenched and Partitioned Steelmentioning

confidence: 99%

Microstructure and Mechanical Properties of an Ultrahigh-Strength 40SiMnNiCr Steel during the One-Step Quenching and Partitioning Process

Lü

et al. 2010

Metall Mater Trans A

153

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The quenching and partitioning (Q&P) process is a novel heat treatment for the enhancement of the strength level of steels without a significant deterioration of ductility. In this work, a study of 40SiMnNiCr steel subjected to the one-step Q&P process is presented. The study results suggest that the strength level of the steel subject to one-step Q&P increases at first and subsequently decreases with the partitioning time because of the synergistic effect of the increase in the retained austenite fraction, the decrease in carbon supersaturation in martensite, the change in the dislocation density in martensite, and the formation of transition carbide. The presence of the transition carbide markedly increases the strength level of the one-step quenched and partitioned steel, with the ultimate tensile strength (UTS) over 2400 MPa and the ductility more than 10 pct during partitioning at 453 K (180°C) for 180 seconds. Isothermal martensite transformation possibly occurred in this medium-carbon ferrous alloy during the one-step Q&P processing. Meanwhile, in the early stages of the low-temperature partitioning process, carbon partitioning from martensite to austenite plays a dominant role in the carbon redistribution competitions. In addition, the relationship between the microstructure and mechanical properties of the one-step quenched and partitioned steel is discussed.

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Large eddy simulation of a round jet into a counterflow

Huai

Zhou

2012

Sci. China Technol. Sci.

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Large eddy simulation of a 3-D spatially developing turbulent round jet

Cited by 8 publications

References 21 publications

Overview of Mechanisms Involved During the Quenching and Partitioning Process in Steels

Overview of Mechanisms Involved During the Quenching and Partitioning Process in Steels

Microstructure and Mechanical Properties of an Ultrahigh-Strength 40SiMnNiCr Steel during the One-Step Quenching and Partitioning Process

Large eddy simulation of a round jet into a counterflow

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